Nuclear magnetic resonance (NMR) techniques are finding increasing use in medical diagnostics. NMR imaging, or magnetic resonance imaging (MRI) as it is sometimes known, has been found to be useful in the detection of a variety of diseases and disorders. MRI has several advantages over other imaging techniques. For example, unlike computerized tomographic methods, MRI does not employ ionizing radiation, and therefore is believed to be safer. Also, MRI can provide more information about soft tissue than can some other imaging methods.
The majority of the NMR techniques developed so far have been based on imaging of hydrogen nuclei. However, other nuclei offer potential advantages with respect to NMR. .sup.19 F in particular is of interest. The fluorine nucleus offers a strong NMR signal magnitude (high gyromagnetic ratio) second only to that of protons. Virtually no imagable fluorine exists naturally in the human body, so no background signal exists; any detectable signal comes only from whatever .sup.19 F has been administered to the subject.
.sup.19 F is a stable isotope and is naturally abundant, so there is no need for isotopic enrichment. Because its gyromagnetic ratio is about 94% that of hydrogen, existing equipment designed to image protons can be inexpensively adapted for .sup.19 F.
Although .sup.19 F NMR has potential benefits, there is a need for new and improved .sup.19 F-containing agents which can be used in NMR imaging and spectroscopy techniques.